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Normal running temperature for BF50D 2016

H

Henriksoele

New member
I have a BF50D from 2016, which have had temperature isssues (vapor lock).
Have cleaned the cooling system as much as possible.
Replaced the insulator in the VST.
New thermostat (second time, just to be sure).
Impeller replaced a year ago, re-checked and looks Ok.

When running, the engine temperature I'm able to read out on my Garmin, rises up to about 85°C, when running at 3000 rpm for some time (water temperature at the moment 20°C)

Anybody knowing whats normal regarding the Engine temperature?
Is 85°C to be expected or too high?

I'm not able to read out (or not able to find it) the temperature which can cause an overtemperature alarm - anybody knowing where to find it an if it's possible on a Garmin at all?

Last testing, gave no issues, everything running fine extcept a maybe too high Engine temperature.
 
Modern Automobiles run at 90c, you should be ok at 85c, especially if you’re running in 20c water.

Honda’s outboard temperature sensors seem to be very sensitive so I would expect your Honda to trigger the alarm if it comes close to an overheat. If your alarm is working, you should be fine imho.
 
Hi,

I'm definitely not expert on this subject but I feel qualified to make some general comments on your question about engine temperature.

You should probably.verify anything I offer as I can assure you it's not "gospel" but more experience
based opinion.

Outboards have "open", unpressurized cooling systems. They differ from "closed", pressurized cooling systems found in most modern vehicle engines.

The difference is important to keep in mind because of the boiling point of water being 212°f (100°c) at 14.7 psi atmospheric pressure (sea level)..

A modern car engine with a 17 psi pressure cap won't experience boil over and coolant vaporization at sea level until approximately 260°f (126°c) while an outboard will begin to experience water vaporization long before that. No water, no cooling.

While I don't have the specification for the BF50D warning and engine protection activation temperature, I think that it's not unreasonable to assume somewhere near 200°f (93°c)

It is my opinion, based on a 140°f (60c) thermostat, the engine should operate in the 140°f (60°c).to 165°f (74°c) range with incoming water temperature of 68°f (20°c)

Also my opinion is that 185°f (85°c) might be considered an elevated temperature at WOT but even more so at only 3000 rpm.

Translation: I think you're running a bit hot and should keep that in mind going forward. However, you're well below alarm temperature and I am just guessing.

It would be important to note here that the first line in many troubleshooting guides for overheating is ENGINE OIL temperature.

Engine oil can cause overheating. It will typically run significantly hotter than the coolant does. I can't provide any specifics as to what it should be or how to accurately measure it for your outboard but it is important that it be the correct oil, clean and fresh.and the level kept near full.

One last thing I'll mention is about you having a vapor lock. boats.net and yumbo only list "2007 and newer" so my access to current info is almost nonexistent. I don't know if the parts depiction of the VST is even relevant to your model. Just pointing out that there's a fuel cooler shown with piping and an in/out cover.(item 9 in link) for water.


For a vapor lock condition it would be judicious to examine the fuel cooler components and plumbing for any restrictions. Moss, algae or other debris can clog the system and prevent or reduce coolant flow.

Good luck.
 
Hi jgmo,

Thanks for your comments, much appreciated.

Regarding "BF50D warning and engine protection activation temperature", I have no information but I know if I have a Warning/power reduction caused by my issue, the temperature in the warning read out is much lower than the temperature I'm able to read via the NMEA2000.
One alarm was 76°C and I remember also one arround 69°C, where my NMEA read out, as far as I remember, was more than 80°C!

"It would be important to note here that the first line in many troubleshooting guides for overheating is ENGINE OIL temperature."
Where do I find those guides?

I'm at the time for an oil service and the last couple of times I have been using "Total Neptune Speeder 10W30" which is a high-performance synthetic-based marine motor oil (have already bought the oil, just need the filter) and before the Total oil, always quicksilver/Mercury 4t Oil.

The Oil level at the momet is a little high (nice and clean oil), so wondering if I have got some gasoline intrusion in to the motor oil, as Honda have had some issues with years ago.

Regarding the fuel cooler, I have been flushing the engine cooling system with acetic acid (32%) a year ago and again a couple of weeks ago, last time with Liqui Moly Marine anti-Lime scale, both times I have had an excellent control beam both from the engine and directly through the fuel cooler.
By the way, when running with the engine at 80-85°C, the cooler and highpressure housing/VST is almost cold (guessing, a little higher than the watertemperature).
Liqui Moly is foaming extremely so it's not as easy to use as acetic acid :-(
 
It appears to me you did a good job cleaning the cooling system, seems very well done.

Your NMEA - I wonder where it is getting its temperature from? Most systems pull the numbers from the ECU so I’d have thought your overheat warning from the ECU and NMEA would be the same?
 
Hi,
What is "an excellent control beam"?

Anyway, an increasing oil level (known as "making oil") is typically a result of the engine running too cool, resulting in an overly rich condition and and not efficiently burning the fuel. This is usually due to a faulty thermostat. That results in combution gas rich in fuel vapor entering the crankcase and condensing. With EFI, it might also indicate faulty injectors.

I recommend running oil level about halfway between the "add" and "full" marks on the dipstick to help prevent oil "churning" from accidental overfill that causes aeration and foaming of the oil. It makes a percieved "making oil" condition easier to monitor too..
OIl analisys is a pain and expensive to do but if your oil is being diluted, it might save your expensive ouboard.
If you suspect dilution, change the oil promptly, monitor closely and take action to stop it asap.

I can't explain the tempeeature discrepency you're seeing other than to say it's possible the engine temperature sensor is faultty. They do go bad. I suppose the ECU could be at fault too but I don't have the experience or documentation to support a recomendation for testing either of those items on that model.

The troubleshooting lists I referred to are in Honda shop manuals. If you have one for your outboard look there. If you don't have a manual, you can purchase one here:

Honda Marine | Shop Manuals Publications | Honda Power Products Support Publications

publications.powerequipment.honda.com publications.powerequipment.honda.com

If you open that link, be sure to check for the free items they offer for your model

Please resist the temptation to "save a couple bucks" by opting for a "knock off" substitute like Seloc or Hayne's as those will likely just frustrate you and possibly end up costing you "gobs-o-dough".

Good luck.
 
Jgmo, would an overly rich condition show up in the spark plugs being wet or otherwise abnormal?

I think it’s possible the odour of gas could be detected on the dipstick or in the oil that is drained.

OP, do you do a lot of low speed trolling- that can cause “making oil”?
 
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H NSDON,

I would have to say yes in many cases but in a making oil situation such as he describes, maybe not. If the cause is running cool, it would likely depend on how long it occurs.

The Tstat could "hang" open for a bit then close and modulate normally during normal operation. That might tend to mask or alleviate fuel fouling of the plugs.

In the case of an injector that "dribbles" after engine off, liquud fuel would likely just flow past the piston and enter the crankcase that way. The plugs might never see a "rich" condition at all. A potentially dangeeous and even explosive condition for the engine.

Never hurts to look at 'em though.
Good suggestion.
 
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